Blender 2.82, two GPU but only one render in Cycle
This is what I get as an answer on Reddit....I think this info will be useful for others.

Windows Task manager does not report multiple GPU correctly. Use a free app called CPUID HWmonitor. Everything else looks good. Make sure you have the latest Nvidia gfx drivers for your GPUs installed.

https://www.nvidia.com/Download/driverResults.aspx/156780/en-us